It's a little sticky faceted cover that goes over your bright pedal LEDs.
The plastic is very slightly smoked to reduce the brightness, and overall it works well.
The adhesive used is good enough when the pedals live on a board, but if you carried them loose in your gig bag the damper may get knocked off.
I would have liked the base of the damper to be made from the same clear plastic so you can see more of the light.
As it is the silver base blocks a lot of the light from anything other that stood dead centre over the pedal. Having some light cast off to the sides would be a help.
As it is though, these diffuse the light really well, they also look good too.
I have them installed on a Vemuram Rage E and RockFabrik Mind Abuse. Both pedals have searing LEDs bit are nicely tamed by these dampers.
I do think in a lot of cases the plain white 'bubble' dampers would be just as good, if not better.
These just look a bit flashier, but do the same job and cost a bit more.